Donnachadh McCarthy, who lives in Camberwell, south London, was one of the first people to start selling the electricity generated by his home back to the grid in 1998.

The eco-auditor who advises homes and business one how to install renewable technology, has a £13,000 photovoltaic cell system and a separate wind turbine on his roof, both generating electricity. A solar water heater provides his hot water, while a £2,800 wood burner system uses waste wood to heat his home.

In total, he has spent almost £23,000 on making his house into a net generator of electricity. He says he received just one £400 grant from the government in total, but has paid more than £3,000 in VAT alone.

"I think the government's record on helping homeonwners install such technology has been useless. The whole grants system is in a complete mess and the figures speak for themselves. Over 10 years in Germany, over 300,000 homes have installed renewables systems. In the UK that figure is just 5,000."

Donnachadh is sceptical that the chancellor's announcement that he wants to increase the amount paid to people who, like him, sell their excess electricity will quickly feed through to his bills.

"In Germany, homes that produce electricity get paid around 50p a unit - here I get just 7p. The best thing the chancellor could have done if he wanted to encourage more micro-generation would be to allow homeowners to offset their capital expenditure against their personal income tax.

"In one stroke it would have transformed the sector and led thousands to start investing in micro-generation projects," he says.